Conductor or
Insulator?

classify a group of items as conductors or insulators of electricity based
on whether the items complete a circuit or not.

Motivation for
Learning

Discrepant Event: Demonstration of How a Light Bulb Works

Materials

Two nails

6" piece of nichrome wire

Bottle or jar

Cork that fits the bottle/jar

At least 4 "D" size batteries or a 6-volt lantern battery

5 Pieces (each no more than 12 inches long) of copper wire if
you are only using four batteries. You will need more wire if you
use more batteries. The ends need to be stripped of insulation.

Assembly

Stick the nails into the cork with the heads of the nails
above the cork

Wrap the one piece of copper wire around the top of each of
the nails. Leave some length of wire free to attach to the
batteries (see figure).

Attach the picture frame wire near the two nail points as
shown in the figure below. The wire can hang down and can be
coiled as long as it does not touch itself. You can coil it around
a pencil before attaching the lose ends to the nail points.

Put the cork in the bottle making sure that the nail points
with the wire are inside the bottle.

Connect the batteries to the ends of the wire. You should now
have 2 pieces of wire that are not attached. These two pieces will
attach to the nail heads when you are ready to do the
demonstration.

NOTES: The thin picture frame wire will get hot and glow. The wire
gets so hot that it burns the air in the bottle. The wire breaks and
the lamp goes out. You will have to use more picture frame wire each
time you want to do the demonstration.

Have an electric lamp ready to show the students. There is no
light bulb to this demonstration so the students usually do not
believe that you can make the wire glow (the glow is brief but
bright).

Have the students use the equipment at their station to make
an electrical tester. If students need a hint tell them that two
ends of two different wires will not attach to anything. (This is
where the items to be tested will be inserted, and the light bulb
will light when the item is a conductor).

Have them draw and label their electrical tester before they
construct it.

*PREDICT FIRST?* Once they have constructed their tester, they
should begin to test all objects in the bag and record on data
sheet.

List the materials from the baggie as either conductors
or insulators.

In the Baggie:

Conductors

Insulators

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

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_______________________

In the classroom:

Conductors

Insulators

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

_______________________

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_______________________

What is an insulator?

What is a conductor?

Tell whether the following objects are conductors or
insulators. Write C for conductors and I for insulators.

_____ Wood-dry _____ Plastic _____Silk _____Gold

_____ Brass _____Chalk _____Fur _____Glass

_____ Clothes _____ Copper _____ Rubber _____Water

What should the light do if there is an insulator
placed between the two wires?

During this experiment, can the tips of your stripped
wires cross each other and touch while trying to test
whether an object is a conductor or an insulator? Explain
your answer.

Extensions

Let the students walk around the classroom and test different
objects in the classroom.

WARN them about sockets and fuse boxes. Do not test
these items.

Students with Special Needs

Some children will need help to actually hook the wires to the battery and
the light. I recommend alligator clips for those children who have physical
disabilities with their hands. If they can not carry the set-up around the room,
you can place it in a plastic box for easier carrying. Have your resource teacher
help you but give them advance warning that you will need their assistance this
day.

Click here for further
information on laboratories with students with special needs.